This invention relates in general to a method of removing contaminants from surfaces and in particular, to a simple, rapid, and effective method of removing from the surface of a quartz resonator a variety of contaminants with which a quartz resonator may possibly come into contact during processing.
It has been recognized in the art that ultraviolet radiation can be used for surface cleaning. That is, in the article "Surface Cleaning By Ultraviolet Radiation" by R. R. Sowell, R. E. Cuthrell, D. M. Mattox, and R. D. Bland appearing in the Journal of Vacuum Science and Technology, Vol. 11, pages 474 to 475, Jan/Feb 1974, and in the article "Surface Cleaning in Thin Film Technology" by D. M. Mattox appearing as a Sandia Laboratory Report SAND 74-0344, Jan. 1975, the authors teach the use of ultraviolet radiation in air to remove contamination from a surface. The use of ultraviolet radiation suggested by the article is not altogether satisfactory in that it requires moving filtered air and takes about 15 hours to work. Moreover, there is no mention of the wavelengths of the ultraviolet radiation to be used, or the need for precleaning.
U.S. Pat. No. 3,914,836, issued Oct. 28, 1975 to Erich Hafner and John R. Vig teaches the use of ultraviolet radiation in the processing of precision quartz crystal resonators. However, the U.S. Pat. No. 3,914,836 method is not completely satisfactory in that the irradiation with ultraviolet must be carried out in an expensive and complex high vacuum system.